Different Measurements with PCI-6033E series

[Loucas]

I have a PCI-6033 E series board  connected on the first end of a SH1006868 cable to  scxi-1000 chassis and a CB-68LPR to the other one.
The configuration works  fine  when i measure thermocouble on an scxi-1100 module or 0-10V on the CB-68LBR (CH16.17.18) terminal use  independently .VI
The problem appears when i try to take both of them in the same .VI. The Vi runs but only the CH16 and SCXI work giving wrong measurements both.
Is It  possible to work on  this configuration or due to the scxi assignment the  board  is  not able to  used  in analog  input the other end??

Thanks
Loucas

[PBear]

Hi Loucas,

It sounds like you have set up the hardware properly with your SH1006868 cable and that the problem is only showing up when you try and perform two separate analog input tasks. If you are trying to perform two separate analog input tasks on your DAQ device simultaneously, you will generally get an error. Are you receiving an error? Ways around this is to pause a task before you start another one. You can set up multiple virtual channels in one task as well.

Another strong possibility, if you are using one task, is ghosting. Ghosting is your board’s ADC not being able to dissipate charge on subsequent channel measurements. To test this and possibly solve your problem, try to space out your three channels to read and ground the intermediate channels. For example, connect your signals to 16, 18, and 19 and ground 17 and 19. Refer to KB 3L8IETLO: How Do I Eliminate Ghosting From My Measurements?

You say wrong measurements are being attained. Can you define this a little more? Are you able to read values from the other channels on your CB-68LBR that is connected by the 68 pin cable labeled “extended” or are they mirror images of CH16?

I hope these things help and you are able to attain the performance you wish.